iOS: How to automatically close the keyboard when user hits Return key in TextField

MyViewController.h

// ===================================================================================
// File's Owner needs to implement UITextFieldDelegate protocol in order for the 
// keyboard to automatically close when the user hits the Return/Enter key.
// 
@interface MyViewController : UIViewController <UITextFieldDelegate> {
    IBOutlet UITextField *userInput; 
} 
@property (nonatomic, retain) UITextField *userInput;
@end

MyViewController.m

// ===================================================================================
// File's Owner needs to implement UITextFieldDelegate protocol in order for the 
// keyboard to automatically close when the user hits the Return/Enter key.
// 
#import "MyViewController.h"

@implementation MyViewController

@synthesize userInput;

- (void)viewDidLoad
{
    self.userInput.delegate = self;
}

-(BOOL)textFieldShouldReturn:(UITextField *)theTextField
{
    if (theTextField == self.userInput) {
        [theTextField resignFirstResponder];
    }
    return YES;
}
@end